[rescue] reading old unix disks from Linux

[John Francini]

VAX Ultrix should be able to run on the SIMH emulator, and it should be able
to mount the disks from the DECstation (which also ran Ultrix).

john

b
John Francini <francini at mac.com>
b
I have come to the conclusion that one useless man is called a disgrace;
that two are called a law firm; and that three or more become a Congress.
And by God I have had *this Congress!b
 b John Adams

> On 26 Apr 2019, at 13:24 , Clem cole <clemc at ccc.com> wrote:
>
> Simh and the like are your friends.    I would only use Linux, MacOS or any
> other Unix to grab the entire disk image as a raw byte stream.    Then run
an
> emulated system such as a simh instance of the native machine that created
it.
> In the case of solaris you ran run Solaris x86 to mount the sparc images.
> Similar AIX PS/2 (386) can read the 370 and romp based disk images.    HPUX
> might be more difficult but you might ask the HP folks in the simh world -
> they have a MPE running but I donbt know about the other OS.
>
> Tru64 can be read on FreeAXP if you donbt gave access to real hw.  I will
> say I have moved scsi disks between my FreeBSD/OpenBSD system and my Alpha
>
>
>
>
> Sent from my PDP-7 Running UNIX V0 expect things to be almost but not
quite.
>
>> On Apr 26, 2019, at 9:11 AM, Doug McIntyre <merlyn at geeks.org> wrote:
>>
>>> On Fri, Apr 26, 2019 at 05:46:57AM -0400, Andrew K. Bressen wrote:
>>> I have old SCSI drives I'm trying to read, and I'm running into a number
>>> of different issues I'd welcome feedback on.
>>>
>>> I've got drives from PCs, Macs, Suns, and DEC machines, and I'm using a
>>> 32 bit linux box (3.x kernel) to read them all. One thing I'm
>>> wondering is if I'd have fewer problems booting off a FreeBSD or NetBSD
>>> liveCD.
>>
>> Honestly, I'd try to get images of those drives read into some virtual
>> format, and run emulators of each of the systems you are trying to
>> read from. Even a PC version of Solaris would probably do much better
>> reading a SPARC solaris disk than any other OS.
>>
>> UFS is not implemented the same. Disk partitioning never was the same.
>> Sun did way different than DEC, which was different than AIX, which
>> was different than HPUX, even if they all used UFS. None of them
>> partitioned the basic disks the same.
>>
>>> In a few cases, I've mounted partitions and seen only a lost+found
>>> directory that's empty. And dated sometime in the 1990s. But if I
>>> run strings(1) on the dd files of the raw partitions, I see tons
>>> of stuff there. So, am I seeing the remains of deleted files, or
>>> is the UFS driver buggy or having a poor interaction with the kernel's
>>> determination of partitions? Is there an undelete tool for antique UFS?
>>
>> I'd think that if you did get it to mount to a point where you could
>> see /lost+found that you found a combination of the proper settings to
>> really read the disk, and most likely the files were "erased", which just
>> means that the directory node entry was removed, and the datablocks
>> put in the available pool (just like any OS does), while leaving
>> the contents of the file still in all its old disk blocks for you to read.
>>
>> BSD systems come with 'fsdb' to repair UFS file systems, but it requires
>> a knowledge of the way UFS works, and lots of manual fiddling.
>> I don't know of any general purpose undelete tools, although I'm sure
>> people have proprietary inhouse solutions somewhere (ie. FBI/NSA/Ontrack)
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